MERCURY

2. very cold giant planets; Neptune and Uranus are the two ice giants in the solar system.
4. in imaginary line where the sky and ground seemed to meet .
5. the Sun the planets and other objects that move around the Sun .
8. Mercury surface space ENvironment GEochemistry and ranging.
10. National Aeronautics and Space Administration; part of U.S. Government responsible for space research .
12. spacecrafts used to gather information about space.
13. an imaginary line on which a planet spins.
16. the layer of gases that surround a planet .
17. the center of a planet .

1. travels across.
3. small objects in space made from dust and ice .
6. the nearly circular path a space object makes around another object in space .
7. people who study space and its objects.
9. a small, solid object in space that circles the Sun .
11. large planets made mostly of gas; Jupiter and Saturn are gas giants .
14. stories or Legends, often about gods or Heroes.
15. large pit or Basin on the surface of a planet .